Hill Descent Control
When the hill descent control switch is pressed, the ATCM sends a hill descent braking assist message to the ABS module over the HS-CAN2. Once the vehicle speed is 3-32 km/h (2-20 mph) and the transmission is in REVERSE or any forward gear, the ABS module uses the hydraulic pump motor and the HCU solenoid valves to maintain the vehicle speed set by the driver. If the vehicle speed is increased or decreased outside of the operational window, the system remains active but descent speed cannot be set or maintained.
The Hill Descent Control feature requires a cool down period after sustained use. The ABS module continually monitors the descent speed, angle of descent, pump motor run time and solenoid valve use. Once the ABS module determines a cool down period is needed, the module sends a message to the GWM over the HS-CAN2. The GWM relays the message to the IPC over the HS-CAN3 to display HILL DESCENT CONTROL OFF SYSTEM COOLING in the message center.
Hill descent control has 3 modes of operation:
- At 3-32 km/h (2-20 mph) when the hill descent control switch is pressed and conditions are correct for hill descent activation, the hill descent control system is enabled and active. The hill descent indicator flashes indicating the feature is active and the message center indicates hill descent control is active.
- At 32-64 km/h (20-40 mph) when the hill descent control switch is pressed and conditions are correct for hill descent activation, the hill descent control system is enabled, but not active. The hill descent control indicator illuminates solidly and a message is displayed in the message center indicating the reason hill descent is not active.
- At more than 64 km/h (40 mph) when the hill descent control switch is pressed, the hill descent control system is not enabled and the hill descent control indicator does not illuminate. The hill descent control feature can only be activated when vehicle speed is below 64 km/h (40 mph).